tree-ssa-pre.c (eliminate): Handle PHI elimination to constants.

2010-06-15  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-pre.c (eliminate): Handle PHI elimination to constants.

	* gcc.dg/tree-ssa/ssa-sccvn-4.c: Adjust.

From-SVN: r160793

gcc/ChangeLog

+2010-06-15  Richard Guenther  <rguenther@suse.de>
+
+	* tree-ssa-pre.c (eliminate): Handle PHI elimination to constants.
+
 2010-06-15  Paul Brook  <paul@codesourcery.com>
  
 	* config/arm/arm.c (use_vfp_abi): Add sorry() for Thumb-1

gcc/testsuite/ChangeLog

 2010-06-15  Richard Guenther  <rguenther@suse.de>
 
+	* gcc.dg/tree-ssa/ssa-sccvn-4.c: Adjust.
+
+2010-06-15  Richard Guenther  <rguenther@suse.de>
+
 	* gcc.dg/vect/bb-slp-21.c: Adjust.
 	* gcc.dg/vect/bb-slp-13.c: Likewise
 	* gcc.dg/vect/bb-slp-4.c: Likewise

gcc/testsuite/gcc.dg/tree-ssa/ssa-sccvn-4.c

@@ -23,5 +23,5 @@ int vnum_test8(int *data)
 } 
 /* We should eliminate m - n, n + k, set data[5] = 0, eliminate the
    address arithmetic for data[5], and set p = 0.
-/* { dg-final { scan-tree-dump-times "Eliminated: 6" 1 "fre"} } */
+/* { dg-final { scan-tree-dump-times "Eliminated: 7" 1 "fre"} } */
 /* { dg-final { cleanup-tree-dump "fre" } } */

gcc/tree-ssa-pre.c

@@ -4330,7 +4330,14 @@ eliminate (void)
 	      else
 		gcc_unreachable ();
 	    }
-	  if (!sprimeexpr
+	  if (!sprime && is_gimple_min_invariant (VN_INFO (res)->valnum))
+	    {
+	      sprime = VN_INFO (res)->valnum;
+	      if (!useless_type_conversion_p (TREE_TYPE (res),
+					      TREE_TYPE (sprime)))
+		sprime = fold_convert (TREE_TYPE (res), sprime);
+	    }
+	  if (!sprime
 	      || sprime == res)
 	    {
 	      gsi_next (&gsi);